Hard Drive Types
There are a few kinds of drives. Spinning disks - either 3.5” @ 7200rpm (faster) or 2.5” @ 5400rmp (slower). Then there are solid state drives (SSDs), there are the 2.5” versions of this (fast) and the NVME version of this (fastest). In addition there are RAIDs, which is a collection of drives in a specific configuration. RAIDs can be made up of all kinds drives, or a mix of drive types. They work best when the drive type is the same IMHO.
External SSD hard drives that can be USB-C or USB-A run faster R/W with USB-C even if the USB-A port is rated at the same speed as USB-C. This is confusing but tested on MAC and PC with Sandisk Extreme Pro
The interfaces below can communicate with a computer in various ways – directly via PCIE or SATA or through a external enclosure and a secondary interface such as USB or Thunderbolt.
| Hard Drive Type | Interface |
Max R/W Speed Sequential |
Average R/W Sustained Speeds Sustained |
| Spinning Disk Drive 3.5" @ 7200 RPM | SATA I/II/III | 210 MB/s | 85 MB/s |
| Spinning Disk Drive 2.5" @ 5400 RPM | SATA I/II/III | 120 MB/s | 60 MB/s |
| Solid State Drive 2.5" | SATA III | 600 MB/s | 450-550 MB/s |
| Solid State Drive NVMe Gen 3 | PCIE 3 | 3,500/3,000 MB/s |
250-1,500 MB/s Depending on temperature and cache |
| Solid State Drive NVMe Gen 4 | PCIE 4 | 7,400/6,800 MB/s | Haven't used one – theoretical |
| Solid State Drive NVMe Gen 5 | PCIE 5 | 14,000/10,000 MB/s | Haven't used one – theoretical |
Format Types
RAIDs
RAIDs are a collection of drives, that when put together, are faster and/or bigger and/or safer. A RAID without any special configuration other than a collective volume is called JBOD ("Just a Bunch of Drives").
RAIDs might have a cache drive that is faster than the rest. Think 4x spinning drives, plus a fifth NVMe.